Works, with rewrites

Cross-posting Bluesky to Reddit: what actually breaks

You can, but not by copying the text across: 4 things change between Bluesky and Reddit, starting with you have 9,700 characters you are not using. Below is exactly what breaks and what to do instead.

Side by side

BlueskyReddit
Characters30010,000
Mediaoptionaloptional
Hashtags1-2 specific hashtagsnone — Reddit has no hashtags
Links in bodyfinefine
Needs platform approvalnoyes

What changes, one by one

You have 9,700 characters you are not using

Bluesky caps at 300 characters, Reddit allows 10,000. Posting the short version verbatim wastes the room Reddit gives you to actually explain the thing.

The hashtag rules are not the same

Bluesky: 1-2 specific hashtags. Reddit: none — Reddit has no hashtags. Carrying the tag block across is the single most obvious sign of an automated cross-post.

Reddit needs a title you never wrote

Reddit requires a separate title (max 300 characters). Bluesky has no such field, so there is nothing to copy across — it has to be written.

Reddit needs approval, Bluesky does not

You can post to Bluesky today with a credential you generate yourself. Reddit gates posting behind a platform review — see our API approval notes for what that actually takes.

Why copy-paste cross-posting underperforms

Bluesky is indie and anti-corporate — polished brand voice reads badly. Reddit is value-first; it must read like a community member, not an ad. Those are different jobs, so the same words cannot do both well — and every algorithm here demotes text that obviously was not written for it. The fix is not to skip cross-posting; it is to send a native version to each network.

Publish to both in one call

curl -X POST https://postwire.io/api/post \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "platforms": ["bluesky", "reddit"],
    "text": "Your post",
    "per_platform": {
      "bluesky": { "text": "The Bluesky version" },
      "reddit": { "text": "The Reddit version" }
    }
  }'

PostWire's /api/generate writes those per-platform versions for you from a single prompt, respecting every limit in the table above. From an AI agent it is one MCP tool call.

Get an API key free →

Questions people actually ask

Can I cross-post from Bluesky to Reddit?
You can, but not by copying the text across: 4 things change between Bluesky and Reddit, starting with you have 9,700 characters you are not using. Below is exactly what breaks and what to do instead.
What is the character limit difference between Bluesky and Reddit?
Bluesky allows 300 characters and Reddit allows 10,000.
How do I post to Bluesky and Reddit at the same time?
With PostWire, one API call publishes to both: POST /api/post with platforms set to ["bluesky","reddit"]. Or one MCP tool call from an AI agent.

Other pairs: Reddit to Bluesky · all combinations · which APIs need approval